The present invention generally relates to containers for storing food items and other perishables and, more specifically, to an improved vacuum canister.
Food, beverages and other perishable items are typically stored in containers such as bottles or canisters. The perishable items stored in such containers, however, deteriorate over time due to air that remains in the container after the container is covered for storage with a lid or cover. The air often contains moisture which further deteriorates the canister contents. Such deterioration may also diminish the natural aroma of the perishable item. In order to prevent such spoilage, it is known to provide vacuum canisters that feature pumps for removing most of the air from the interior of the canister after it is sealed.
In addition to removing air from the interior of the canister, the vacuum assists in maintaining the seal between the canister and the canister lid. As a result, prior art vacuum canisters also typically include a release valve so that the vacuum in the canister may be released prior to removal of the canister lid. In addition to featuring a pump and a vacuum release valve, a number of prior art vacuum canisters feature a vacuum indicator so that the user knows when air has been evacuated from the canister.
An example of a prior art vacuum canister is presented in U.S. Pat. No. 5,692,632 to Hsieh et al. The container of the Hsieh et al. '632 patent includes a lid with a built-in pump. More specifically the lid features a button in its top that, when depressed, forces a piston downwards in a pumping chamber. The piston is connected to the button by a piston rod containing a conduit that leads from the pumping chamber to the exterior of the container. As a result, when the button is pressed down, air below the piston travels out of the pumping chamber through the piston rod conduit to the exterior of the container.
In addition, as the piston of the Hsieh et al. '632 patent moves downward, air from the interior of the container enters the portion of the pumping chamber above the piston through a one-way valve. When the button is released, the piston travels upward due to the force exerted by a compression spring. As the piston travels upward, the air above the piston travels through holes in the periphery of the piston, past an O-ring, to the portion of the pumping chamber below the piston. The downward pumping stroke of the button may then be repeated. The O-ring seals the holes in the periphery of the piston, and also seals the gap between the periphery of the piston and the pumping chamber wall, during the downward pumping stroke so that air may only escape the portion of the pumping chamber below the piston through the piston rod conduit.
While the pumping system of the Hsieh et al. '632 patent works well, the creation of the multiple holes in the periphery of the piston increases manufacturing complexity and costs as does the O-ring seal and the piston rod conduit. In addition, the holes may become clogged or otherwise obstructed which would adversely effect pumping performance. A further disadvantage of the container of the Hsieh et al. '632 patent is that it does not feature a vacuum indicator.
As mentioned previously, a number of prior art vacuum containers provide vacuum indicators. An example of such a container is presented in U.S. Pat. No. 5,803,282 to Chen et al. In addition to including a vacuum pump, the lid features a bellows with an open bottom end that is in communication with the interior of the container. A compression spring is positioned within the bellows and urges the upper end of the bellows upwards out of an aperture formed in the top surface of the lid. As a result, when air has not been evacuated from the container, the upper end of the bellows protrudes up from the top surface of the lid. When air has been evacuated from the container, however, the resulting vacuum pulls the upper end of the bellows down into the aperture so that the presence of the vacuum is indicated to a user.
The container of the Chen et al. '282 patent also includes a vacuum release valve for releasing the vacuum in the container so that the container lid may be easily removed. The valve includes knob which, when pressed downwards, unseats an O-ring so that the interior of the container is permitted to communicate with the surrounding atmosphere through an aperture.
While both the vacuum indicator and release valve of the container of the Chen et al. '282 patent work well, it would be advantageous to combine their functions into a single device. Such an approach would streamline the appearance of the container. In addition, operation of the device would be simplified and more intuitive as users may often instinctively press in on the vacuum indicator of the Chen et al. '282 patent expecting to release the vacuum instead of searching for a separate release valve.
Accordingly, it is an object of the present invention to provide an improved vacuum canister that features a pumping mechanism that is durable and easy to operate.
It is another object of the present invention to provide an improved vacuum canister with a vacuum indicator that indicates when air has been evacuated from the canister.
It is another object of the present invention to provide an improved vacuum canister with a vacuum indicator that also functions as a vacuum release valve.
It is still another object of the present invention to provide an improved vacuum canister that is simple and economical to manufacture.
These and other objects and advantages will be apparent from the following specification.